Re-set M55-FS Cast Mag. - Worked Great (for a short time)

[jbfrost912]

I re-set my slide damper with two Magnehelic meters ( one digital, one analog). Ran stove on setting 5 for an hour and then adjusted slide damper. After re-adjusting and waiting for fire to level out I had the best flame and temperature with the mag. reading at .19. I could run the stove with the mag in the .15-.17 range but the flame was dark orange, black tips and lazy, also the temperature was a lot lower. I ran the stove back on my normal settings with the thermostat overnight and yesterday and now it appears that the flame is back to where it was before I re-set my slide damper. The damper is now set a little more than halfway in.

Here are my readings for my test:
Pellets: Spruce Pointe
Mag reading on high: .19
Temp of back plate: 731 degrees
I check my temps with an infrared thermometer.
Mag reading on setting 3: .18
Mag reading on setting 1: .16-.17

Today my mag. reading on setting 3: .24

How can this change overnight?
Before I did my re-set I totally cleaned the stove ( burnpot, ashpan, stovepipe, top plate, back plate, cleanout Tee), to try and get a good reading. I don't think that the stove can be that dirty in less than 24 hours.

Yesterday when I was checking the stove temps on setting 3 my backplate was at 400-410 degrees after 15 minutes of burn time. Today I can only reach around 360 degrees after 30+ minutes of burning on setting 3.

Do these stoves have a demo program or something in them? This is the third time I have done my slide damper set-up with the same results.
The dealer that set up the stove the first time is no longer in business and I haven't been able to reach anyone at Enviro.
Any info would be a great help.
Thanks,
Jon

 

[jtakeman]

Hey Jon,

I don't own the M55 cast so I'm guessing a bit. The damper can drift if not secure. Did you lock the damper after adjustment?

 

[flynfrfun]

Was there wind when you set your mag? Maybe it was blowing into your exhaust causing a false reading? I still question your mag's accuracy because even at .15 my flame is not lazy. It has to get down to about .13 before that happens. Either that or my gauge is off. But, I doubt it because the factory recommends .15-.17 which gives me a good flame on mine.

Talking about only leaving the stove on for 15mins. What do you mean? 15min from the time you hit the power button? If so, the temp will be hotter at that point because the stove is still in it's start cycle which dumps more pellets than when it's up and running. My stove takes a good hr or more to really get all the way up to temp. That's why I start it at heat level 5, watch the temps rise until I know they are at the typical range it runs on #3 (240F) and then drop it to #3. Otherwise if I leave it on #3 from startup, it can take 2hrs, sometimes more to get fully and completely heated up. It all depends on how fast I'm looking to heat the downstairs though.

 

[jbfrost912]

I had put some marks on the slide damper and it was still in the same spot.
I don't think that it was windy out when I was doing the test.
The 15 minutes I was talking about was (after the stove has been cycling on high/low all night and the morning) when the stove kicks up to heat setting #3 and then bring the temp up to satisfiy the thermostat. I also noticed that today it was taking longer than usual to bring the temps up even with the outside temps colder.

To get my stove to get down to .13 on the mag I have to close the damper all the way in. Then I get a bad flame with a lot of ash also.
The annoying thing is that I will make an adjustment to something whether it be the slide damper or the feed rate or the combustion air and it work better for a little while and then go back to where it is now.

Thanks for the questions.

 

[skinanbones]

If your setup is the one in your avatar, my first thought would be have you cleaned the cap outside or the horizontal section of pipe. i would even clean the vertical section even though not much soot builds up there. I had this issue a couple years back with a Empress and it turned out the horizontal pipe was down to about a 3/4 inch.

 

[jbfrost912]

Yes, I cleaned out the stovepipe: the vertical and the horizontal. The only area that I did not check was right before the combustion blower. There is a removable plate where the exhaust sensor is.

 

[flynfrfun]

I don't think cleaning is the problem. A dirty stove should have lower readings than a clean stove. Besides with the 4" exhaust pipe Enviro is having us install, it would take A LOT of ash to even start to change the way the stove works. I'm wondering if something is not sealing correctly like the hopper cover gasket, door gasket or ash door gasket. Maybe one of them has a gasket out of position or torn and is causing the readings to change each time you open the hopper as sometimes it seals, sometimes it doesn't? Of course a leaky gasket would cause lower readings like a dirty stove, but I'm just brainstorming ways for the readings to CHANGE from day to day that much. Was the damper in the same exact position from the day you set it at .19 and then it went to .24 the next day? If none of these are the problem I'm thinking it's got to be either a faulty control panel or faulty exhaust blower. You are lucky with the freestanding stove in that you can put a voltmeter on the exhaust blower motor and see just what is going to it and see if it's fluctuating over time.

 

[jbfrost912]

The slider damper was in the same position and did not move.

Unfortunately, I forgot my meters at work, but I would like to check the voltages.
I was also noticing that this batch of pellets are a lot smaller pieces than the last batch I had. I don't know if this would make a difference.

 

[flynfrfun]

I don't think the pellets would make much difference, but I guess it's possible. The smaller pellets will allow more lbs/hr to feed which will give you more heat and a more consistent feed (less of the big fire, then little fire and more of a steady sized flame).

One thing to keep in mind is that as the stove heats up, the mag readings drop. So when you set your damper the other day at .19 it was with the stove running at #5 for 1hr or more right? Then the next day when you got the .24 reading...had the stove been running at #5 for 1hr or more when you took the reading? The reason I ask is the readings will start higher and then gradually drop as the stove heats up. I remember a post from a forum member (Brad) and I think his started at .28 and as the stove heated up all the way it dropped down to something like .22 before he even touched the damper.

Another question. Even though it went back to .24 is the flame good? Or did it change also?

 

[jbfrost912]

The flame seemed a little smaller, but the heat ouput was much less.

 

[flynfrfun]

How can you tell the heat output is less? I saw you said you were using an IR thermometer and measuring the backplate? What part are you calling the backplate? The best way is to use a meat thermometer and mount it into a convection tube. Make sure it doesn't touch any metal though. This way you are measure actual output air of your stove. The temp of metal parts of the stove is irrelevant as long as your output air is hot. Here are some pics of my setup. I had to modify the mounting clip to fit into the slot above the convection tubes and bend it so that the probe is centered in the tube.

 

[jtakeman]

The pellets themselfs won't change the reading on the mag. But the heat they produce might? But it should only be minimal differences if any. Heat will expand the metal of the stove and help seal any minimal leaks AFAIK. Probably why they want it run for an hour to get the stove to full temp before adjustments. As the stove heats up the reading should drop?

I agree with flyn, Set the mag on high after a good long burn and lock it in. Then set the stove on the setting you run on the most and check the mag reading after at least a half hour or so. Just so you have a reading to keep an eye on. A baseline of sorts to keep tabs on it. If you need to adjust use the blower trim adjustments on the control panel instead of tweaking the damper. Always let it run to get it up to temp before you check the readings. I wouldn't check it on cold starts or after it just came off the lower heat setting.

I would start by checking voltage's on the blower and doing some leak checks if this doesn't stablize once you set it up like the manual says. Keep us posted!

Flyn, Can you check your blower voltages? Just in case Jon needs to compare. I don't see any base lines in the Manual's that Enviro has released. Might be good info for others as well????

 

[flynfrfun]

Mine is an insert so I'd have to make some jumpers for my voltmeter to be able to do it. May not get to it for a while since it requires me to slide my stove out. Hopefully someone with a freestanding can get it as that should be easier for them.

 

[jbfrost912]

flyn,
I took the temps on the back liner right above the chute in the fire chamber. I was just trying to get a temp from the same spot.
When you had taken the picture of the thermo on your stove do you know what setting it was on?
I think I will try to get some air temps with a temp probe.

Jay,
I will check my voltages when I get my meters from work. I thought I saw a chart somewhere with the voltages with each heat setting.
I had talked to a guy at Enviro and he had checked some numbers and said to try and do a check on the vacuum chamber by jumping out one of the switches and starting the stove on #5.
I can then find out if the numbers match when it left the factory.

It seems like my stove works better at 25 degrees or more (performance wise). I thought that a wood burning device worked better with colder air?

Thanks for your help.

 

[jtakeman]

I seen the chart in the tech manual, But nothing for the M55 AFAIK. I'd just make sure it is not at line voltage in the lower heat settings.

Don't know what he has you jumping out? Maybe the high limit switch?? Shouldn't be necesary AFAIK.

 

[flynfrfun]

I'm not an expert on IR thermometer usage, but have read that trying to take temps thru the glass is flaky at best. Yeah, ditch the IR thermometer, they are just too finicky for the type of measurement you need to take. Too many variables using one and they can't measure the output air which is what you really need to know.

I took that temp on heat level 3, feed trim 2 combustion trim 3. That was using Blazer pellets. My current pellets, I get about 250F with heat level 3, feed trim 3. Also, if you're looking to compare to my #'s you might as well put the probe in the same hole. Mine is in the 2nd from the left. The left side of the stove is hotter than the right. Of course unless you are going to burn Blazers, your temps will likely be different. But at least you can check temps at different mag readings.

Is there some way your exhaust cap is the type that could be causing a vacuum when the wind blows? Does it stick up above the roof? Is it in the leeward side of the house where a low pressure zone could be created as the wind flows around the house?

J is on the right track though...once you are able to check voltages at the motor at least you will know if it's always running full tilt or not. That will at least confirm or eliminate that component.

 

[jbfrost912]

It is the exhaust sensor. I think it makes the stove think it has proof of flame. When you turn the stove on, you can change the heat setting, trim setting and think the pellet type (don't quote me on the last one, as I haven't tried it yet). They must do this at the factory to check for leaks? Mine was reading .32 on the mag when it left the factory on heat setting #5 with a cold start.